extensions/browser/extension_registrar.cc - chromium/src - Git at Google

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "extensions/browser/extension_registrar.h"

 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/stl_util.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/devtools_agent_host.h"
 #include "content/public/browser/notification_service.h"
 #include "extensions/browser/app_sorting.h"
 #include "extensions/browser/extension_host.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/lazy_context_id.h"
 #include "extensions/browser/lazy_context_task_queue.h"
 #include "extensions/browser/notification_types.h"
 #include "extensions/browser/process_manager.h"
 #include "extensions/browser/renderer_startup_helper.h"
 #include "extensions/browser/runtime_data.h"
 #include "extensions/browser/service_worker_task_queue.h"
 #include "extensions/common/manifest_handlers/background_info.h"

 using content::DevToolsAgentHost;

 namespace extensions {

 ExtensionRegistrar::ExtensionRegistrar(content::BrowserContext* browser_context,
                                        Delegate* delegate)
     : browser_context_(browser_context),
       delegate_(delegate),
       extension_system_(ExtensionSystem::Get(browser_context)),
       extension_prefs_(ExtensionPrefs::Get(browser_context)),
       registry_(ExtensionRegistry::Get(browser_context)),
       renderer_helper_(
           RendererStartupHelperFactory::GetForBrowserContext(browser_context)),
       weak_factory_(this) {}

 ExtensionRegistrar::~ExtensionRegistrar() = default;

 void ExtensionRegistrar::AddExtension(
     scoped_refptr<const Extension> extension) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   bool is_extension_upgrade = false;
   bool is_extension_loaded = false;
   const Extension* old = registry_->GetInstalledExtension(extension->id());
   if (old) {
     is_extension_loaded = true;
     int version_compare_result = extension->version().CompareTo(old->version());
     is_extension_upgrade = version_compare_result > 0;
     // Other than for unpacked extensions, we should not be downgrading.
     if (!Manifest::IsUnpackedLocation(extension->location()) &&
         version_compare_result < 0) {
       UMA_HISTOGRAM_ENUMERATION(
           "Extensions.AttemptedToDowngradeVersionLocation",
           extension->location(), Manifest::NUM_LOCATIONS);
       UMA_HISTOGRAM_ENUMERATION("Extensions.AttemptedToDowngradeVersionType",
                                 extension->GetType(), Manifest::NUM_LOAD_TYPES);

       // TODO(https://crbug.com/810799): It would be awfully nice to CHECK this,
       // but that's caused problems. There are apparently times when this
       // happens that we aren't accounting for. We should track those down and
       // fix them, but it can be tricky.
       NOTREACHED() << "Attempted to downgrade extension."
                    << "\nID: " << extension->id()
                    << "\nOld Version: " << old->version()
                    << "\nNew Version: " << extension->version()
                    << "\nLocation: " << extension->location();
       return;
     }
   }

   // If the extension was disabled for a reload, we will enable it.
   bool was_reloading = reloading_extensions_.erase(extension->id()) > 0;

   // Set the upgraded bit; we consider reloads upgrades.
   extension_system_->runtime_data()->SetBeingUpgraded(
       extension->id(), is_extension_upgrade || was_reloading);

   // The extension is now loaded; remove its data from unloaded extension map.
   unloaded_extension_paths_.erase(extension->id());

   // If a terminated extension is loaded, remove it from the terminated list.
   UntrackTerminatedExtension(extension->id());

   // Notify the delegate we will add the extension.
   delegate_->PreAddExtension(extension.get(), old);

   if (was_reloading) {
     ReplaceReloadedExtension(extension);
   } else {
     if (is_extension_loaded) {
       // To upgrade an extension in place, remove the old one and then activate
       // the new one. ReloadExtension disables the extension, which is
       // sufficient.
       RemoveExtension(extension->id(), UnloadedExtensionReason::UPDATE);
     }
     AddNewExtension(extension);
   }

   extension_system_->runtime_data()->SetBeingUpgraded(extension->id(), false);
 }

 void ExtensionRegistrar::AddNewExtension(
     scoped_refptr<const Extension> extension) {
   if (extension_prefs_->IsExtensionBlacklisted(extension->id())) {
     DCHECK(!Manifest::IsComponentLocation(extension->location()));
     // Only prefs is checked for the blacklist. We rely on callers to check the
     // blacklist before calling into here, e.g. CrxInstaller checks before
     // installation then threads through the install and pending install flow
     // of this class, and ExtensionService checks when loading installed
     // extensions.
     registry_->AddBlacklisted(extension);
   } else if (delegate_->ShouldBlockExtension(extension.get())) {
     DCHECK(!Manifest::IsComponentLocation(extension->location()));
     registry_->AddBlocked(extension);
   } else if (extension_prefs_->IsExtensionDisabled(extension->id())) {
     registry_->AddDisabled(extension);
     // Notify that a disabled extension was added or updated.
     content::NotificationService::current()->Notify(
         extensions::NOTIFICATION_EXTENSION_UPDATE_DISABLED,
         content::Source<content::BrowserContext>(browser_context_),
         content::Details<const Extension>(extension.get()));
   } else {  // Extension should be enabled.
     // All apps that are displayed in the launcher are ordered by their ordinals
     // so we must ensure they have valid ordinals.
     if (extension->RequiresSortOrdinal()) {
       AppSorting* app_sorting = extension_system_->app_sorting();
       app_sorting->SetExtensionVisible(extension->id(),
                                        extension->ShouldDisplayInNewTabPage());
       app_sorting->EnsureValidOrdinals(extension->id(),
                                        syncer::StringOrdinal());
     }
     registry_->AddEnabled(extension);
     ActivateExtension(extension.get(), true);
   }
 }

 void ExtensionRegistrar::RemoveExtension(const ExtensionId& extension_id,
                                          UnloadedExtensionReason reason) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   int include_mask =
       ExtensionRegistry::EVERYTHING & ~ExtensionRegistry::TERMINATED;
   scoped_refptr<const Extension> extension(
       registry_->GetExtensionById(extension_id, include_mask));

   // If the extension was already removed, just notify of the new unload reason.
   // TODO: It's unclear when this needs to be called given that it may be a
   // duplicate notification. See crbug.com/708230.
   if (!extension) {
     extension_system_->UnregisterExtensionWithRequestContexts(extension_id,
                                                               reason);
     return;
   }

   // Keep information about the extension so that we can reload it later
   // even if it's not permanently installed.
   unloaded_extension_paths_[extension->id()] = extension->path();

   // Stop tracking whether the extension was meant to be enabled after a reload.
   reloading_extensions_.erase(extension->id());

   if (registry_->disabled_extensions().Contains(extension_id)) {
     // The extension is already deactivated.
     registry_->RemoveDisabled(extension->id());
     extension_system_->UnregisterExtensionWithRequestContexts(extension_id,
                                                               reason);
   } else {
     // TODO(michaelpg): The extension may be blocked or blacklisted, in which
     // case it shouldn't need to be "deactivated". Determine whether the removal
     // notifications are necessary (crbug.com/708230).
     registry_->RemoveEnabled(extension_id);
     DeactivateExtension(extension.get(), reason);
   }

   content::NotificationService::current()->Notify(
       extensions::NOTIFICATION_EXTENSION_REMOVED,
       content::Source<content::BrowserContext>(browser_context_),
       content::Details<const Extension>(extension.get()));
 }

 void ExtensionRegistrar::EnableExtension(const ExtensionId& extension_id) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   // If the extension is currently reloading, it will be enabled once the reload
   // is complete.
   if (reloading_extensions_.count(extension_id) > 0)
     return;

   // First, check that the extension can be enabled.
   if (IsExtensionEnabled(extension_id) ||
       extension_prefs_->IsExtensionBlacklisted(extension_id) ||
       registry_->blocked_extensions().Contains(extension_id)) {
     return;
   }

   const Extension* extension =
       registry_->disabled_extensions().GetByID(extension_id);
   if (extension && !delegate_->CanEnableExtension(extension))
     return;

   // Now that we know the extension can be enabled, update the prefs.
   extension_prefs_->SetExtensionEnabled(extension_id);

   // This can happen if sync enables an extension that is not installed yet.
   if (!extension)
     return;

   // Actually enable the extension.
   registry_->AddEnabled(extension);
   registry_->RemoveDisabled(extension->id());
   ActivateExtension(extension, false);
 }

 void ExtensionRegistrar::DisableExtension(const ExtensionId& extension_id,
                                           int disable_reasons) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   DCHECK_NE(disable_reason::DISABLE_NONE, disable_reasons);

   if (extension_prefs_->IsExtensionBlacklisted(extension_id))
     return;

   // The extension may have been disabled already. Just add the disable reasons.
   // TODO(michaelpg): Move this after the policy check, below, to ensure that
   // disable reasons disallowed by policy are not added here.
   if (!IsExtensionEnabled(extension_id)) {
     extension_prefs_->AddDisableReasons(extension_id, disable_reasons);
     return;
   }

   scoped_refptr<const Extension> extension =
       registry_->GetExtensionById(extension_id, ExtensionRegistry::EVERYTHING);

   bool is_controlled_extension =
       !delegate_->CanDisableExtension(extension.get());

   if (is_controlled_extension) {
     // Remove disallowed disable reasons.
     // Certain disable reasons are always allowed, since they are more internal
     // to the browser (rather than the user choosing to disable the extension).
     int internal_disable_reason_mask =
         extensions::disable_reason::DISABLE_RELOAD |
         extensions::disable_reason::DISABLE_CORRUPTED |
         extensions::disable_reason::DISABLE_UPDATE_REQUIRED_BY_POLICY |
         extensions::disable_reason::DISABLE_BLOCKED_BY_POLICY;
     disable_reasons &= internal_disable_reason_mask;

     if (disable_reasons == disable_reason::DISABLE_NONE)
       return;
   }

   extension_prefs_->SetExtensionDisabled(extension_id, disable_reasons);

   int include_mask =
       ExtensionRegistry::EVERYTHING & ~ExtensionRegistry::DISABLED;
   extension = registry_->GetExtensionById(extension_id, include_mask);
   if (!extension)
     return;

   // The extension is either enabled or terminated.
   DCHECK(registry_->enabled_extensions().Contains(extension->id()) ||
          registry_->terminated_extensions().Contains(extension->id()));

   // Move the extension to the disabled list.
   registry_->AddDisabled(extension);
   if (registry_->enabled_extensions().Contains(extension->id())) {
     registry_->RemoveEnabled(extension->id());
     DeactivateExtension(extension.get(), UnloadedExtensionReason::DISABLE);
   } else {
     // The extension must have been terminated. Don't send additional
     // notifications for it being disabled.
     bool removed = registry_->RemoveTerminated(extension->id());
     DCHECK(removed);
   }
 }

 void ExtensionRegistrar::ReloadExtension(
     const ExtensionId extension_id,  // Passed by value because reloading can
                                      // invalidate a reference to the ID.
     LoadErrorBehavior load_error_behavior) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   // If the extension is already reloading, don't reload again.
   if (extension_prefs_->HasDisableReason(extension_id,
                                          disable_reason::DISABLE_RELOAD)) {
     return;
   }

   // Ignore attempts to reload a blacklisted or blocked extension. Sometimes
   // this can happen in a convoluted reload sequence triggered by the
   // termination of a blacklisted or blocked extension and a naive attempt to
   // reload it. For an example see http://crbug.com/373842.
   if (registry_->blacklisted_extensions().Contains(extension_id) ||
       registry_->blocked_extensions().Contains(extension_id)) {
     return;
   }

   base::FilePath path;

   const Extension* enabled_extension =
       registry_->enabled_extensions().GetByID(extension_id);

   // Disable the extension if it's loaded. It might not be loaded if it crashed.
   if (enabled_extension) {
     // If the extension has an inspector open for its background page, detach
     // the inspector and hang onto a cookie for it, so that we can reattach
     // later.
     // TODO(yoz): this is not incognito-safe!
     ProcessManager* manager = ProcessManager::Get(browser_context_);
     ExtensionHost* host = manager->GetBackgroundHostForExtension(extension_id);
     if (host && content::DevToolsAgentHost::HasFor(host->host_contents())) {
       // Look for an open inspector for the background page.
       scoped_refptr<content::DevToolsAgentHost> agent_host =
           content::DevToolsAgentHost::GetOrCreateFor(host->host_contents());
       agent_host->DisconnectWebContents();
       orphaned_dev_tools_[extension_id] = agent_host;
     }

     path = enabled_extension->path();
     // BeingUpgraded is set back to false when the extension is added.
     extension_system_->runtime_data()->SetBeingUpgraded(enabled_extension->id(),
                                                         true);
     DisableExtension(extension_id, disable_reason::DISABLE_RELOAD);
     DCHECK(registry_->disabled_extensions().Contains(extension_id));
     reloading_extensions_.insert(extension_id);
   } else {
     std::map<ExtensionId, base::FilePath>::const_iterator iter =
         unloaded_extension_paths_.find(extension_id);
     if (iter == unloaded_extension_paths_.end()) {
       return;
     }
     path = unloaded_extension_paths_[extension_id];
   }

   delegate_->LoadExtensionForReload(extension_id, path, load_error_behavior);
 }

 void ExtensionRegistrar::TerminateExtension(const ExtensionId& extension_id) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   scoped_refptr<const Extension> extension =
       registry_->enabled_extensions().GetByID(extension_id);
   if (!extension)
     return;

   // Keep information about the extension so that we can reload it later
   // even if it's not permanently installed.
   unloaded_extension_paths_[extension->id()] = extension->path();

   DCHECK(!base::ContainsKey(reloading_extensions_, extension->id()))
       << "Enabled extension shouldn't be marked for reloading";

   registry_->AddTerminated(extension);
   registry_->RemoveEnabled(extension_id);
   DeactivateExtension(extension.get(), UnloadedExtensionReason::TERMINATE);
 }

 void ExtensionRegistrar::UntrackTerminatedExtension(
     const ExtensionId& extension_id) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   scoped_refptr<const Extension> extension =
       registry_->terminated_extensions().GetByID(extension_id);
   if (!extension)
     return;

   registry_->RemoveTerminated(extension_id);

   // TODO(michaelpg): This notification was already sent when the extension was
   // unloaded as part of being terminated. But we send it again as observers
   // may be tracking the terminated extension. See crbug.com/708230.
   content::NotificationService::current()->Notify(
       extensions::NOTIFICATION_EXTENSION_REMOVED,
       content::Source<content::BrowserContext>(browser_context_),
       content::Details<const Extension>(extension.get()));
 }

 bool ExtensionRegistrar::IsExtensionEnabled(
     const ExtensionId& extension_id) const {
   if (registry_->enabled_extensions().Contains(extension_id) ||
       registry_->terminated_extensions().Contains(extension_id)) {
     return true;
   }

   if (registry_->disabled_extensions().Contains(extension_id) ||
       registry_->blacklisted_extensions().Contains(extension_id) ||
       registry_->blocked_extensions().Contains(extension_id)) {
     return false;
   }

   if (delegate_->ShouldBlockExtension(nullptr))
     return false;

   // If the extension hasn't been loaded yet, check the prefs for it. Assume
   // enabled unless otherwise noted.
   return !extension_prefs_->IsExtensionDisabled(extension_id) &&
          !extension_prefs_->IsExtensionBlacklisted(extension_id) &&
          !extension_prefs_->IsExternalExtensionUninstalled(extension_id);
 }

 void ExtensionRegistrar::DidCreateRenderViewForBackgroundPage(
     ExtensionHost* host) {
   auto iter = orphaned_dev_tools_.find(host->extension_id());
   if (iter == orphaned_dev_tools_.end())
     return;
   // Keepalive count is reset on extension reload. This re-establishes the
   // keepalive that was added when the DevTools agent was initially attached.
   ProcessManager::Get(browser_context_)
       ->IncrementLazyKeepaliveCount(host->extension(), Activity::DEV_TOOLS,
                                     std::string());
   iter->second->ConnectWebContents(host->host_contents());
   orphaned_dev_tools_.erase(iter);
 }

 void ExtensionRegistrar::ActivateExtension(const Extension* extension,
                                            bool is_newly_added) {
   // The URLRequestContexts need to be first to know that the extension
   // was loaded. Otherwise a race can arise where a renderer that is created
   // for the extension may try to load an extension URL with an extension id
   // that the request context doesn't yet know about. The BrowserContext should
   // ensure its URLRequestContexts appropriately discover the loaded extension.
   extension_system_->RegisterExtensionWithRequestContexts(
       extension,
       base::Bind(&ExtensionRegistrar::OnExtensionRegisteredWithRequestContexts,
                  weak_factory_.GetWeakPtr(), WrapRefCounted(extension)));

   renderer_helper_->OnExtensionLoaded(*extension);

   // TODO(lazyboy): We should move all logic that is required to start up an
   // extension to a separate class, instead of calling adhoc methods like
   // service worker ones below.
   if (BackgroundInfo::IsServiceWorkerBased(extension)) {
     DCHECK(extension->is_extension());
     ServiceWorkerTaskQueue::Get(browser_context_)->ActivateExtension(extension);
   }

   // Tell subsystems that use the ExtensionRegistryObserver::OnExtensionLoaded
   // about the new extension.
   //
   // NOTE: It is important that this happen after notifying the renderers about
   // the new extensions so that if we navigate to an extension URL in
   // ExtensionRegistryObserver::OnExtensionLoaded the renderer is guaranteed to
   // know about it.
   registry_->TriggerOnLoaded(extension);

   delegate_->PostActivateExtension(extension);

   // When an existing extension is re-enabled, it may be necessary to spin up
   // its lazy background page.
   if (!is_newly_added)
     MaybeSpinUpLazyBackgroundPage(extension);
 }

 void ExtensionRegistrar::DeactivateExtension(const Extension* extension,
                                              UnloadedExtensionReason reason) {
   registry_->TriggerOnUnloaded(extension, reason);
   renderer_helper_->OnExtensionUnloaded(*extension);
   extension_system_->UnregisterExtensionWithRequestContexts(extension->id(),
                                                             reason);
   if (BackgroundInfo::IsServiceWorkerBased(extension)) {
     ServiceWorkerTaskQueue::Get(browser_context_)
         ->DeactivateExtension(extension);
   }
   delegate_->PostDeactivateExtension(extension);
 }

 bool ExtensionRegistrar::ReplaceReloadedExtension(
     scoped_refptr<const Extension> extension) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   // The extension must already be disabled, and the original extension has
   // been unloaded.
   CHECK(registry_->disabled_extensions().Contains(extension->id()));
   if (!delegate_->CanEnableExtension(extension.get()))
     return false;

   // TODO(michaelpg): Other disable reasons might have been added after the
   // reload started. We may want to keep the extension disabled and just remove
   // the DISABLE_RELOAD reason in that case.
   extension_prefs_->SetExtensionEnabled(extension->id());

   // Move it over to the enabled list.
   CHECK(registry_->RemoveDisabled(extension->id()));
   CHECK(registry_->AddEnabled(extension));

   ActivateExtension(extension.get(), false);

   return true;
 }

 void ExtensionRegistrar::OnExtensionRegisteredWithRequestContexts(
     scoped_refptr<const Extension> extension) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

   registry_->AddReady(extension);
   if (registry_->enabled_extensions().Contains(extension->id()))
     registry_->TriggerOnReady(extension.get());
 }

 void ExtensionRegistrar::MaybeSpinUpLazyBackgroundPage(
     const Extension* extension) {
   if (!BackgroundInfo::HasLazyBackgroundPage(extension))
     return;

   // For orphaned devtools, we will reconnect devtools to it later in
   // DidCreateRenderViewForBackgroundPage().
   bool has_orphaned_dev_tools =
       base::ContainsKey(orphaned_dev_tools_, extension->id());

   // Reloading component extension does not trigger install, so RuntimeAPI won't
   // be able to detect its loading. Therefore, we need to spin up its lazy
   // background page.
   bool is_component_extension =
       Manifest::IsComponentLocation(extension->location());

   if (!has_orphaned_dev_tools && !is_component_extension)
     return;

   // Wake up the event page by posting a dummy task.
   const LazyContextId context_id(browser_context_, extension->id());
   context_id.GetTaskQueue()->AddPendingTask(context_id, base::DoNothing());
 }

 }  // namespace extensions
	// Copyright 2017 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "extensions/browser/extension_registrar.h"

	#include "base/bind.h"
	#include "base/bind_helpers.h"
	#include "base/logging.h"
	#include "base/metrics/histogram_macros.h"
	#include "base/stl_util.h"
	#include "content/public/browser/browser_context.h"
	#include "content/public/browser/browser_thread.h"
	#include "content/public/browser/devtools_agent_host.h"
	#include "content/public/browser/notification_service.h"
	#include "extensions/browser/app_sorting.h"
	#include "extensions/browser/extension_host.h"
	#include "extensions/browser/extension_prefs.h"
	#include "extensions/browser/extension_registry.h"
	#include "extensions/browser/extension_system.h"
	#include "extensions/browser/lazy_context_id.h"
	#include "extensions/browser/lazy_context_task_queue.h"
	#include "extensions/browser/notification_types.h"
	#include "extensions/browser/process_manager.h"
	#include "extensions/browser/renderer_startup_helper.h"
	#include "extensions/browser/runtime_data.h"
	#include "extensions/browser/service_worker_task_queue.h"
	#include "extensions/common/manifest_handlers/background_info.h"

	using content::DevToolsAgentHost;

	namespace extensions {

	ExtensionRegistrar::ExtensionRegistrar(content::BrowserContext* browser_context,
	Delegate* delegate)
	: browser_context_(browser_context),
	delegate_(delegate),
	extension_system_(ExtensionSystem::Get(browser_context)),
	extension_prefs_(ExtensionPrefs::Get(browser_context)),
	registry_(ExtensionRegistry::Get(browser_context)),
	renderer_helper_(
	RendererStartupHelperFactory::GetForBrowserContext(browser_context)),
	weak_factory_(this) {}

	ExtensionRegistrar::~ExtensionRegistrar() = default;

	void ExtensionRegistrar::AddExtension(
	scoped_refptr<const Extension> extension) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	bool is_extension_upgrade = false;
	bool is_extension_loaded = false;
	const Extension* old = registry_->GetInstalledExtension(extension->id());
	if (old) {
	is_extension_loaded = true;
	int version_compare_result = extension->version().CompareTo(old->version());
	is_extension_upgrade = version_compare_result > 0;
	// Other than for unpacked extensions, we should not be downgrading.
	if (!Manifest::IsUnpackedLocation(extension->location()) &&
	version_compare_result < 0) {
	UMA_HISTOGRAM_ENUMERATION(
	"Extensions.AttemptedToDowngradeVersionLocation",
	extension->location(), Manifest::NUM_LOCATIONS);
	UMA_HISTOGRAM_ENUMERATION("Extensions.AttemptedToDowngradeVersionType",
	extension->GetType(), Manifest::NUM_LOAD_TYPES);

	// TODO(https://crbug.com/810799): It would be awfully nice to CHECK this,
	// but that's caused problems. There are apparently times when this
	// happens that we aren't accounting for. We should track those down and
	// fix them, but it can be tricky.
	NOTREACHED() << "Attempted to downgrade extension."
	<< "\nID: " << extension->id()
	<< "\nOld Version: " << old->version()
	<< "\nNew Version: " << extension->version()
	<< "\nLocation: " << extension->location();
	return;
	}
	}

	// If the extension was disabled for a reload, we will enable it.
	bool was_reloading = reloading_extensions_.erase(extension->id()) > 0;

	// Set the upgraded bit; we consider reloads upgrades.
	extension_system_->runtime_data()->SetBeingUpgraded(
	extension->id(), is_extension_upgrade \|\| was_reloading);

	// The extension is now loaded; remove its data from unloaded extension map.
	unloaded_extension_paths_.erase(extension->id());

	// If a terminated extension is loaded, remove it from the terminated list.
	UntrackTerminatedExtension(extension->id());

	// Notify the delegate we will add the extension.
	delegate_->PreAddExtension(extension.get(), old);

	if (was_reloading) {
	ReplaceReloadedExtension(extension);
	} else {
	if (is_extension_loaded) {
	// To upgrade an extension in place, remove the old one and then activate
	// the new one. ReloadExtension disables the extension, which is
	// sufficient.
	RemoveExtension(extension->id(), UnloadedExtensionReason::UPDATE);
	}
	AddNewExtension(extension);
	}

	extension_system_->runtime_data()->SetBeingUpgraded(extension->id(), false);
	}

	void ExtensionRegistrar::AddNewExtension(
	scoped_refptr<const Extension> extension) {
	if (extension_prefs_->IsExtensionBlacklisted(extension->id())) {
	DCHECK(!Manifest::IsComponentLocation(extension->location()));
	// Only prefs is checked for the blacklist. We rely on callers to check the
	// blacklist before calling into here, e.g. CrxInstaller checks before
	// installation then threads through the install and pending install flow
	// of this class, and ExtensionService checks when loading installed
	// extensions.
	registry_->AddBlacklisted(extension);
	} else if (delegate_->ShouldBlockExtension(extension.get())) {
	DCHECK(!Manifest::IsComponentLocation(extension->location()));
	registry_->AddBlocked(extension);
	} else if (extension_prefs_->IsExtensionDisabled(extension->id())) {
	registry_->AddDisabled(extension);
	// Notify that a disabled extension was added or updated.
	content::NotificationService::current()->Notify(
	extensions::NOTIFICATION_EXTENSION_UPDATE_DISABLED,
	content::Source<content::BrowserContext>(browser_context_),
	content::Details<const Extension>(extension.get()));
	} else { // Extension should be enabled.
	// All apps that are displayed in the launcher are ordered by their ordinals
	// so we must ensure they have valid ordinals.
	if (extension->RequiresSortOrdinal()) {
	AppSorting* app_sorting = extension_system_->app_sorting();
	app_sorting->SetExtensionVisible(extension->id(),
	extension->ShouldDisplayInNewTabPage());
	app_sorting->EnsureValidOrdinals(extension->id(),
	syncer::StringOrdinal());
	}
	registry_->AddEnabled(extension);
	ActivateExtension(extension.get(), true);
	}
	}

	void ExtensionRegistrar::RemoveExtension(const ExtensionId& extension_id,
	UnloadedExtensionReason reason) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	int include_mask =
	ExtensionRegistry::EVERYTHING & ~ExtensionRegistry::TERMINATED;
	scoped_refptr<const Extension> extension(
	registry_->GetExtensionById(extension_id, include_mask));

	// If the extension was already removed, just notify of the new unload reason.
	// TODO: It's unclear when this needs to be called given that it may be a
	// duplicate notification. See crbug.com/708230.
	if (!extension) {
	extension_system_->UnregisterExtensionWithRequestContexts(extension_id,
	reason);
	return;
	}

	// Keep information about the extension so that we can reload it later
	// even if it's not permanently installed.
	unloaded_extension_paths_[extension->id()] = extension->path();

	// Stop tracking whether the extension was meant to be enabled after a reload.
	reloading_extensions_.erase(extension->id());

	if (registry_->disabled_extensions().Contains(extension_id)) {
	// The extension is already deactivated.
	registry_->RemoveDisabled(extension->id());
	extension_system_->UnregisterExtensionWithRequestContexts(extension_id,
	reason);
	} else {
	// TODO(michaelpg): The extension may be blocked or blacklisted, in which
	// case it shouldn't need to be "deactivated". Determine whether the removal
	// notifications are necessary (crbug.com/708230).
	registry_->RemoveEnabled(extension_id);
	DeactivateExtension(extension.get(), reason);
	}

	content::NotificationService::current()->Notify(
	extensions::NOTIFICATION_EXTENSION_REMOVED,
	content::Source<content::BrowserContext>(browser_context_),
	content::Details<const Extension>(extension.get()));
	}

	void ExtensionRegistrar::EnableExtension(const ExtensionId& extension_id) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	// If the extension is currently reloading, it will be enabled once the reload
	// is complete.
	if (reloading_extensions_.count(extension_id) > 0)
	return;

	// First, check that the extension can be enabled.
	if (IsExtensionEnabled(extension_id) \|\|
	extension_prefs_->IsExtensionBlacklisted(extension_id) \|\|
	registry_->blocked_extensions().Contains(extension_id)) {
	return;
	}

	const Extension* extension =
	registry_->disabled_extensions().GetByID(extension_id);
	if (extension && !delegate_->CanEnableExtension(extension))
	return;

	// Now that we know the extension can be enabled, update the prefs.
	extension_prefs_->SetExtensionEnabled(extension_id);

	// This can happen if sync enables an extension that is not installed yet.
	if (!extension)
	return;

	// Actually enable the extension.
	registry_->AddEnabled(extension);
	registry_->RemoveDisabled(extension->id());
	ActivateExtension(extension, false);
	}

	void ExtensionRegistrar::DisableExtension(const ExtensionId& extension_id,
	int disable_reasons) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
	DCHECK_NE(disable_reason::DISABLE_NONE, disable_reasons);

	if (extension_prefs_->IsExtensionBlacklisted(extension_id))
	return;

	// The extension may have been disabled already. Just add the disable reasons.
	// TODO(michaelpg): Move this after the policy check, below, to ensure that
	// disable reasons disallowed by policy are not added here.
	if (!IsExtensionEnabled(extension_id)) {
	extension_prefs_->AddDisableReasons(extension_id, disable_reasons);
	return;
	}

	scoped_refptr<const Extension> extension =
	registry_->GetExtensionById(extension_id, ExtensionRegistry::EVERYTHING);

	bool is_controlled_extension =
	!delegate_->CanDisableExtension(extension.get());

	if (is_controlled_extension) {
	// Remove disallowed disable reasons.
	// Certain disable reasons are always allowed, since they are more internal
	// to the browser (rather than the user choosing to disable the extension).
	int internal_disable_reason_mask =
	extensions::disable_reason::DISABLE_RELOAD \|
	extensions::disable_reason::DISABLE_CORRUPTED \|
	extensions::disable_reason::DISABLE_UPDATE_REQUIRED_BY_POLICY \|
	extensions::disable_reason::DISABLE_BLOCKED_BY_POLICY;
	disable_reasons &= internal_disable_reason_mask;

	if (disable_reasons == disable_reason::DISABLE_NONE)
	return;
	}

	extension_prefs_->SetExtensionDisabled(extension_id, disable_reasons);

	int include_mask =
	ExtensionRegistry::EVERYTHING & ~ExtensionRegistry::DISABLED;
	extension = registry_->GetExtensionById(extension_id, include_mask);
	if (!extension)
	return;

	// The extension is either enabled or terminated.
	DCHECK(registry_->enabled_extensions().Contains(extension->id()) \|\|
	registry_->terminated_extensions().Contains(extension->id()));

	// Move the extension to the disabled list.
	registry_->AddDisabled(extension);
	if (registry_->enabled_extensions().Contains(extension->id())) {
	registry_->RemoveEnabled(extension->id());
	DeactivateExtension(extension.get(), UnloadedExtensionReason::DISABLE);
	} else {
	// The extension must have been terminated. Don't send additional
	// notifications for it being disabled.
	bool removed = registry_->RemoveTerminated(extension->id());
	DCHECK(removed);
	}
	}

	void ExtensionRegistrar::ReloadExtension(
	const ExtensionId extension_id, // Passed by value because reloading can
	// invalidate a reference to the ID.
	LoadErrorBehavior load_error_behavior) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	// If the extension is already reloading, don't reload again.
	if (extension_prefs_->HasDisableReason(extension_id,
	disable_reason::DISABLE_RELOAD)) {
	return;
	}

	// Ignore attempts to reload a blacklisted or blocked extension. Sometimes
	// this can happen in a convoluted reload sequence triggered by the
	// termination of a blacklisted or blocked extension and a naive attempt to
	// reload it. For an example see http://crbug.com/373842.
	if (registry_->blacklisted_extensions().Contains(extension_id) \|\|
	registry_->blocked_extensions().Contains(extension_id)) {
	return;
	}

	base::FilePath path;

	const Extension* enabled_extension =
	registry_->enabled_extensions().GetByID(extension_id);

	// Disable the extension if it's loaded. It might not be loaded if it crashed.
	if (enabled_extension) {
	// If the extension has an inspector open for its background page, detach
	// the inspector and hang onto a cookie for it, so that we can reattach
	// later.
	// TODO(yoz): this is not incognito-safe!
	ProcessManager* manager = ProcessManager::Get(browser_context_);
	ExtensionHost* host = manager->GetBackgroundHostForExtension(extension_id);
	if (host && content::DevToolsAgentHost::HasFor(host->host_contents())) {
	// Look for an open inspector for the background page.
	scoped_refptr<content::DevToolsAgentHost> agent_host =
	content::DevToolsAgentHost::GetOrCreateFor(host->host_contents());
	agent_host->DisconnectWebContents();
	orphaned_dev_tools_[extension_id] = agent_host;
	}

	path = enabled_extension->path();
	// BeingUpgraded is set back to false when the extension is added.
	extension_system_->runtime_data()->SetBeingUpgraded(enabled_extension->id(),
	true);
	DisableExtension(extension_id, disable_reason::DISABLE_RELOAD);
	DCHECK(registry_->disabled_extensions().Contains(extension_id));
	reloading_extensions_.insert(extension_id);
	} else {
	std::map<ExtensionId, base::FilePath>::const_iterator iter =
	unloaded_extension_paths_.find(extension_id);
	if (iter == unloaded_extension_paths_.end()) {
	return;
	}
	path = unloaded_extension_paths_[extension_id];
	}

	delegate_->LoadExtensionForReload(extension_id, path, load_error_behavior);
	}

	void ExtensionRegistrar::TerminateExtension(const ExtensionId& extension_id) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	scoped_refptr<const Extension> extension =
	registry_->enabled_extensions().GetByID(extension_id);
	if (!extension)
	return;

	// Keep information about the extension so that we can reload it later
	// even if it's not permanently installed.
	unloaded_extension_paths_[extension->id()] = extension->path();

	DCHECK(!base::ContainsKey(reloading_extensions_, extension->id()))
	<< "Enabled extension shouldn't be marked for reloading";

	registry_->AddTerminated(extension);
	registry_->RemoveEnabled(extension_id);
	DeactivateExtension(extension.get(), UnloadedExtensionReason::TERMINATE);
	}

	void ExtensionRegistrar::UntrackTerminatedExtension(
	const ExtensionId& extension_id) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	scoped_refptr<const Extension> extension =
	registry_->terminated_extensions().GetByID(extension_id);
	if (!extension)
	return;

	registry_->RemoveTerminated(extension_id);

	// TODO(michaelpg): This notification was already sent when the extension was
	// unloaded as part of being terminated. But we send it again as observers
	// may be tracking the terminated extension. See crbug.com/708230.
	content::NotificationService::current()->Notify(
	extensions::NOTIFICATION_EXTENSION_REMOVED,
	content::Source<content::BrowserContext>(browser_context_),
	content::Details<const Extension>(extension.get()));
	}

	bool ExtensionRegistrar::IsExtensionEnabled(
	const ExtensionId& extension_id) const {
	if (registry_->enabled_extensions().Contains(extension_id) \|\|
	registry_->terminated_extensions().Contains(extension_id)) {
	return true;
	}

	if (registry_->disabled_extensions().Contains(extension_id) \|\|
	registry_->blacklisted_extensions().Contains(extension_id) \|\|
	registry_->blocked_extensions().Contains(extension_id)) {
	return false;
	}

	if (delegate_->ShouldBlockExtension(nullptr))
	return false;

	// If the extension hasn't been loaded yet, check the prefs for it. Assume
	// enabled unless otherwise noted.
	return !extension_prefs_->IsExtensionDisabled(extension_id) &&
	!extension_prefs_->IsExtensionBlacklisted(extension_id) &&
	!extension_prefs_->IsExternalExtensionUninstalled(extension_id);
	}

	void ExtensionRegistrar::DidCreateRenderViewForBackgroundPage(
	ExtensionHost* host) {
	auto iter = orphaned_dev_tools_.find(host->extension_id());
	if (iter == orphaned_dev_tools_.end())
	return;
	// Keepalive count is reset on extension reload. This re-establishes the
	// keepalive that was added when the DevTools agent was initially attached.
	ProcessManager::Get(browser_context_)
	->IncrementLazyKeepaliveCount(host->extension(), Activity::DEV_TOOLS,
	std::string());
	iter->second->ConnectWebContents(host->host_contents());
	orphaned_dev_tools_.erase(iter);
	}

	void ExtensionRegistrar::ActivateExtension(const Extension* extension,
	bool is_newly_added) {
	// The URLRequestContexts need to be first to know that the extension
	// was loaded. Otherwise a race can arise where a renderer that is created
	// for the extension may try to load an extension URL with an extension id
	// that the request context doesn't yet know about. The BrowserContext should
	// ensure its URLRequestContexts appropriately discover the loaded extension.
	extension_system_->RegisterExtensionWithRequestContexts(
	extension,
	base::Bind(&ExtensionRegistrar::OnExtensionRegisteredWithRequestContexts,
	weak_factory_.GetWeakPtr(), WrapRefCounted(extension)));

	renderer_helper_->OnExtensionLoaded(*extension);

	// TODO(lazyboy): We should move all logic that is required to start up an
	// extension to a separate class, instead of calling adhoc methods like
	// service worker ones below.
	if (BackgroundInfo::IsServiceWorkerBased(extension)) {
	DCHECK(extension->is_extension());
	ServiceWorkerTaskQueue::Get(browser_context_)->ActivateExtension(extension);
	}

	// Tell subsystems that use the ExtensionRegistryObserver::OnExtensionLoaded
	// about the new extension.
	//
	// NOTE: It is important that this happen after notifying the renderers about
	// the new extensions so that if we navigate to an extension URL in
	// ExtensionRegistryObserver::OnExtensionLoaded the renderer is guaranteed to
	// know about it.
	registry_->TriggerOnLoaded(extension);

	delegate_->PostActivateExtension(extension);

	// When an existing extension is re-enabled, it may be necessary to spin up
	// its lazy background page.
	if (!is_newly_added)
	MaybeSpinUpLazyBackgroundPage(extension);
	}

	void ExtensionRegistrar::DeactivateExtension(const Extension* extension,
	UnloadedExtensionReason reason) {
	registry_->TriggerOnUnloaded(extension, reason);
	renderer_helper_->OnExtensionUnloaded(*extension);
	extension_system_->UnregisterExtensionWithRequestContexts(extension->id(),
	reason);
	if (BackgroundInfo::IsServiceWorkerBased(extension)) {
	ServiceWorkerTaskQueue::Get(browser_context_)
	->DeactivateExtension(extension);
	}
	delegate_->PostDeactivateExtension(extension);
	}

	bool ExtensionRegistrar::ReplaceReloadedExtension(
	scoped_refptr<const Extension> extension) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	// The extension must already be disabled, and the original extension has
	// been unloaded.
	CHECK(registry_->disabled_extensions().Contains(extension->id()));
	if (!delegate_->CanEnableExtension(extension.get()))
	return false;

	// TODO(michaelpg): Other disable reasons might have been added after the
	// reload started. We may want to keep the extension disabled and just remove
	// the DISABLE_RELOAD reason in that case.
	extension_prefs_->SetExtensionEnabled(extension->id());

	// Move it over to the enabled list.
	CHECK(registry_->RemoveDisabled(extension->id()));
	CHECK(registry_->AddEnabled(extension));

	ActivateExtension(extension.get(), false);

	return true;
	}

	void ExtensionRegistrar::OnExtensionRegisteredWithRequestContexts(
	scoped_refptr<const Extension> extension) {
	DCHECK_CURRENTLY_ON(content::BrowserThread::UI);

	registry_->AddReady(extension);
	if (registry_->enabled_extensions().Contains(extension->id()))
	registry_->TriggerOnReady(extension.get());
	}

	void ExtensionRegistrar::MaybeSpinUpLazyBackgroundPage(
	const Extension* extension) {
	if (!BackgroundInfo::HasLazyBackgroundPage(extension))
	return;

	// For orphaned devtools, we will reconnect devtools to it later in
	// DidCreateRenderViewForBackgroundPage().
	bool has_orphaned_dev_tools =
	base::ContainsKey(orphaned_dev_tools_, extension->id());

	// Reloading component extension does not trigger install, so RuntimeAPI won't
	// be able to detect its loading. Therefore, we need to spin up its lazy
	// background page.
	bool is_component_extension =
	Manifest::IsComponentLocation(extension->location());

	if (!has_orphaned_dev_tools && !is_component_extension)
	return;

	// Wake up the event page by posting a dummy task.
	const LazyContextId context_id(browser_context_, extension->id());
	context_id.GetTaskQueue()->AddPendingTask(context_id, base::DoNothing());
	}

	} // namespace extensions